High Levels Of Nitrite Research Articles

Denitrification Kinetics of High‐Strength Nitrate in Granular Sludge Reactors

Biological denitrification of high‐strength nitrate is challenging due to building‐up of toxic nitrite to high levels. In this study, denitrification kinetics of high‐strength nitrate is investigated in a granular sludge reactor operated in sequencing batch mode. The nitrate concentrations are increased from 677, 1355, 2032, 2710, 3387, 4065–4742 mg L−1 NO3N in the reactor. Carbon and an electron source (acetate) are supplied at a fixed acetate‐carbon to nitrate‐nitrogen ratio of 1.5. At steady state, complete denitrification of 4742 mg L−1 NO3N in the feed is observed within the first 20 h of sequencing batch reactor (SBR) cycle. High denitrification rate constants are observed for NO3N concentrations from 677 to 2032 mg L−1. However, a decrease in denitrification rate constants is observed for nitrate‐N concentrations of 2710–4742 mg L−1, due to inhibition caused by transient accumulation of high levels of nitrite. Denitrifying biomass formed in the SBR is predominantly consisted of granular sludge, containing cocci, and rod‐shaped microorganisms. Cultivation of nitrite‐tolerant, denitrifying microbial community in granular sludge will help in the development of high rate reactors needed for process application.

Protective effect of carnosine and N-acetylcysteine against sodium nitrite-induced oxidative stress and DNA damage in rat intestine

The widespread use of sodium nitrite (NaNO2) as food preservative, rampant use of nitrogenous fertilizers for agricultural practices, and improper disposal of nitrogenous wastes have drastically increased human exposure to high nitrite levels causing various health disorders and death. In the present study, the protective effect of carnosine and N-acetylcysteine (NAC) against NaNO2-induced intestinal toxicity in rats was investigated. Animals were given a single acute oral dose of NaNO2 at 60mg/kg body weight with or without prior administration of either carnosine at 100mg/kg body weight/day for 7days or NAC at 100mg/kg body weight/day for 5days. Rats were killed after 24h, and intestinal preparations were used for the evaluation of biochemical alterations and histological abrasions. Administration of NaNO2 alone decreased the activities of intestinal brush border membrane and metabolic enzymes and significantly weakened the anti-oxidant defense system. DNA damage was also evident as observed by increased DNA-protein crosslinking and fragmentation. However, prior administration of carnosine or NAC significantly ameliorated NaNO2-induced damage in intestinal cells. Histological studies support these biochemical results, showing intestinal damage in NaNO2-treated animals and reduced tissue injury in the combination groups. The intrinsic anti-oxidant properties of carnosine and NAC must have contributed to the observed mitigation of nitrite-induced metabolic alterations and oxidative damage. Based on further validation from clinical trials, carnosine and NAC can potentially be used as chemo-preventive agents against NaNO2 toxicity.

Caracterisation Physico-Chimique Du Lixiviat De La Decharge Sauvage De Meknes

Solid and urban waste produced by the municipality of Meknes amounts to more than 185.103 tons annually. Since 2002 they have been transported to a landfill controlled, wild of an area of 23 hectares on the outskirts of the Commune. This discharge is unfortunately devoid of a leachate treatment device (brownish liquid effluent, produced under the combined action of rainwater and fermentation of buried waste). This study aims to make a physico-chemical characterization and evaluate the states mineral and organic of this leachate. It should be noted that this physicochemical characterization is arbitrary because this discharge will soon be equipped with a waste disposal and recovery center (CEV) using Evalixm as a treatment method. Since 2014, the company '' SUEZ ''Environment began to put in place under control this discharge. For the realization of this characterization, we carried out a series of sampling leachate from June 2014 to June 2015. During this period, the physico-chemical analyzes carried out on these samples, revealed: - low levels of nitrates (NO3 - max = 18,1 mg / L) and phosphates (PO4 3- max = 0,38mg / L) - high levels of ammonium (NH4 + max = 54,13 mg / L) and nitrites (NO 2 - , max = 27,67mg / L). This mineral concentration is translated by a high electrical conductivity which has reached a maximum value of 7.35 10 3 μS / cm. Organic pollution estimated by the pollutant load is important; the values of the Calculated DCO from 1205 to 9207 mg O2 / L with an average of 4808 mg O2 / L, those of DBO are between 53 and 386 mg O2/ L for an average of 157 mg O2 / L. The values of the ratio DBO5 / DCO oscillate between 0.01 and 0.08 with an average of 0.04. This which testifies to the anaerobic character that prevails at the level of the discharge and a probable contamination of the water table. The hydrogen variant (pH) between 6,42 and 8,99 is an annual average of 8,42 which shows that the leachate produced by the landfill is basic. The pH value shows a stagnation (8.42 and 8.23) from one year to the next, reflecting its stability and aging

Carnosine and N-acetyl cysteine protect against sodium nitrite-induced oxidative stress in rat blood.

Sodium nitrite (NaNO2 ) is widely used in the food industry as a preservative and colorant in meat and fish products. Industrialization and improper agricultural practices have greatly increased human exposure to high nitrite levels, mainly through contaminated drinking water, causing various health disorders. We have investigated the protective effect of carnosine (CAR) and N-acetyl cysteine (NAC) on NaNO2 -induced toxicity in rat blood. CAR is a bioactive dipeptide found in mammalian muscle while NAC is a synthetic sulfhydryl amino acid and an important precursor of glutathione. Animals were given a single acute oral dose of NaNO2 at 60 mg/kg body weight with or without prior administration of either CAR or NAC. Rats were sacrificed after 24 h, blood was withdrawn and plasma and erythrocytes were isolated. Administration of NaNO2 alone increased methemoglobin levels and methemoglobin reductase activity, decreased the activities of antioxidant defense and metabolic enzymes and significantly weakened the total antioxidant capacity of rat erythrocytes. Similar effects were seen in plasma of NaNO2 -treated rats. In contrast, administration of CAR or NAC, prior to NaNO2 treatment, markedly attenuated the NaNO2 -elicited deleterious effects. Thus, CAR and NAC can mitigate nitrite-induced metabolic alterations and oxidative damage probably due to their intrinsic biochemical antioxidant properties. This study suggests that CAR and NAC can be potentially used as therapeutic/protective agents against NaNO2 toxicity.

Antigenicity, immunogenicity and protective efficacy of a conserved Leishmania hypothetical protein against visceral leishmaniasis.

In this study, a Leishmania hypothetical protein, LiHyS, was evaluated regarding its antigenicity, immunogenicity and protective efficacy against visceral leishmaniasis (VL). Regarding antigenicity, immunoblottings and an enzyme-linked immunosorbent assay using human and canine sera showed high sensitivity and specificity values for the recombinant protein (rLiHyS) in the diagnosis of VL. When evaluating the immunogenicity of LiHyS, which is possibly located in the parasite's flagellar pocket, proliferative assays using peripheral blood mononuclear cells from healthy subjects or VL patients showed a high proliferative index in both individuals, when compared to the results obtained using rA2 or unstimulated cultures. Later, rLiHyS/saponin was inoculated in BALB/c mice, which were then challenged with Leishmania infantum promastigotes. The vaccine induced an interferon-γ, interleukin (IL)-12 and granulocyte-macrophage colony-stimulating factor production, which was maintained after infection and which was associated with high nitrite and IgG2a antibody levels, as well as low IL-4 and IL-10 production. Significant reductions in the parasite load in liver, spleen, bone marrow and draining lymph nodes were found in these animals. In this context, the present study shows that the rLiHyS has the capacity to be evaluated as a diagnostic marker or vaccine candidate against VL.

Interaction of "Candidatus Accumulibacter" and nitrifying bacteria to achieve energy-efficient denitrifying phosphorus removal via nitrite pathway from sewage.

To achieve energy-efficient denitrifying phosphorus removal via nitrite pathway from sewage, interaction of "Candidatus Accumulibacter" and nitrifying bacteria was investigated in a continuous-flow process. When nitrite in returned sludge of secondary settler was above 13mg/L, nitrite inhibition on anaerobic P-release of poly-phosphate organisms (PAOs) occurred. Clades IIC and IID were dominant, reaching 3.1%-11.9% of total bacteria. Clade IIC was sensitive to nitrite. Under low concentration of nitrite (<8mg/L), clade IIC primarily contributed to anoxic P-uptake. Clade IID had a strong tolerance to nitrite exposure. At high nitrite level (above 16mg/L), anoxic P-uptake was mainly performed by clade IID due to its strong tolerance to nitrite exposure. Ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and Accumulibacter interacted through variations of nitrite accumulation. High AOB abundance coupled with inhibition of NOB favored denitrifying phosphorus removal by clade IID. All Accumulibacter lineages were sorted into four clades of Type II. The most dominant ppk1 gene homologs were affiliated with clade IID, accounting for 69% of ppk1 clone library, and thus played an important role in denitrifying phosphorus removal via nitrite pathway.

Impairment of osmotic challenge-induced neurohypophyseal hormones secretion in sepsis survivor rats.

Recent studies have reported that sepsis survivors show impaired central nervous system functions. The osmoregulation in this post-sepsis condition has not been well investigated. In the present study, we evaluated the secretion of neurohypophyseal hormones, arginine vasopressin (AVP) and oxytocin (OT), and water intake induced by osmotic challenge in survivor rats. Wistar rats were submitted to sepsis by cecal ligation and puncture (CLP). Five days after CLP surgery, the survivor and naive animals were stimulated with an osmotic challenge consisting of hypertonic saline administration. Thirty minutes later, blood and brain were collected for determination of osmolality, nitrite, interleukin (IL)-1β, IL-6, AVP and OT levels and c-fos expression analysis of hypothalamic supraoptic nuclei (SON), respectively. In another set of sepsis survivor animals, water intake was measured for 240min after the osmotic stimulus. High levels of nitrite and IL-1β, but not IL-6, were found in the plasma of sepsis survivors and this long-term systemic inflammation was not altered by the osmotic challenge. Moreover, the AVP and OT secretion (but not the osmolality) and c-fos expression in SON were significantly attenuated in CLP survivor animals. Additionally, there was no alteration in the water intake response induced by osmotic challenge in the sepsis survivor group. The results suggest that the inflammatory components mediated a persistent impairment in the component of the osmoregulatory reflex affecting the secretion of neurohypophyseal hormones in sepsis survivor animals.

Blood collection vials and clinically used intravenous fluids contain significant amounts of nitrite

The biology of the inorganic anion nitrite is linked to nitric oxide (NO) as nitrite can be reduced to NO and mediate its biological activities. Thus, studies of nitrite biology require sensitive and selective chemical assays. The acetic and ascorbic acids method is selective for nitrite and measures it in biological matrices. However, one of the pitfalls of nitrite measurements is its ubiquitous presence in sample collection tubes. Here, we showed high levels of nitrite in collection tubes containing EDTA, sodium citrate or sodium heparin and smaller amounts in tubes containing lithium heparin or serum clot activator. We also showed the presence of nitrite in colloid and crystalloid solutions frequently administered to patients and found variable levels of nitrite in 5% albumin, 0.9% sodium chloride, lactated ringer's, and dextrose-plus-sodium chloride solutions. These levels of nitrite varied across lots and manufacturers of the same type of fluid. Because these fluids are administered intravenously to patients (including those in shock), sometimes in large volumes (liters), it is possible that infusions of these nitrite-containing fluids may have clinical implications. A protocol for blood collection free of nitrite contamination was developed and used to examine nitrite levels in whole blood, red blood cells, plasma and urine from normal volunteers. Nitrite measurements were reproducible, had minimal variability, and did not indicate sex-differences. These findings validated a method and protocol for selective nitrite assay in biological fluids free of nitrite contamination which can be applied for study of diseases where dysfunctional NO signaling has been implicated.

Acute oral dose of sodium nitrite induces redox imbalance, DNA damage, metabolic and histological changes in rat intestine.

Industrialization and unchecked use of nitrate/nitrite salts for various purposes has increased human exposure to high levels of sodium nitrite (NaNO2) which can act as a pro-oxidant and pro-carcinogen. Oral exposure makes the gastrointestinal tract particularly susceptible to nitrite toxicity. In this work, the effect of administration of a single acute oral dose of NaNO2 on rat intestine was studied. Animals were randomly divided into four groups and given single doses of 20, 40, 60 and 75 mg NaNO2/kg body weight. Untreated animals served as the control group. An NaNO2 dose-dependent decline in the activities of brush border membrane enzymes, increase in lipid peroxidation, protein oxidation, hydrogen peroxide levels and decreased thiol content was observed in all treated groups. The activities of various metabolic and antioxidant defense enzymes were also altered. NaNO2 induced a dose-dependent increase in DNA damage and DNA-protein crosslinking. Histopathological studies showed marked morphological damage in intestinal cells. The intestinal damage might be due to nitrite-induced oxidative stress, direct action of nitrite anion or chemical modification by reaction intermediates.

Nitrate and nitrite exposure affect cognitive behavior and oxygen consumption during exercise in zebrafish

Humans concentrate nitrate from dietary or endogenous sources in the salivary glands, which is then reduced to nitrite, swallowed, and absorbed. Circulating nitrite acts as a reservoir for nitric oxide (NO) with its reduction to NO potentiated in acidic or hypoxic areas, such as contracting skeletal muscle. NO is an important signaling molecule with a short half‐life that regulates cardiovascular function, cellular energetics, and neurotransmission among other things. In humans, consumption of supplemental nitrate reduces blood pressure and decreases the oxygen cost of exercise, but we do not have a complete understanding of how dietary nitrate or nitrite is metabolized particularly in the presence of exercise. We used a stable isotope‐assisted metabolomics approach to assess nitrate and nitrite metabolism with and without exercise, and tested the hypothesis that nitrate and nitrite exposure reduces the cost of exercise and improves cognitive function in a zebrafish model.Adult zebrafish were exposed to either sodium nitrate (606.9 mg/L), sodium nitrite (19.5 mg/L), or control water for 21 days (n=60–66). A subset of the fish were switched to 100% 15N‐nitrite or 15N‐nitrate for the final 3 days of the exposure. Tissue nitrite and nitrate were quantified using diaminonaphthalene (DAN) derivatization and subsequently analyzed on a 3200 ABSciex QTRAP. Nitrite and nitrate exposure increased tissue nitrite (230% and 340%, respectively) and tissue nitrate (150% and 250%, respectively), and significant increases in nitrate and nitrite in blood were also observed. Nitrate exposure significantly decreased oxygen consumption during exercise in the AutoResp exercise assay. Nitrite treatment increased oxygen consumption with exercise but pathological examination indicated nitrite exposure caused mild gill damage. Metabolomics showed that up to 90% of the tissue nitrite and nitrate can be derived from exogenous sources. The data supports existing data that a feedback mechanism that inhibits endogenous NO production when high levels of nitrite or nitrate are consumed. Nitrite was depleted during exercise in all treatment groups, indicating potential increased utilization of nitrite as a substrate for NO production in hypoxia.In a free swim test nitrate and nitrite treatment significantly increased the duration of time spent in the bottom of the tank which is a possible indicator of anxiety. Nitrate treated fish also had a significant decline in movement following a startle but this was not detected in nitrite treated fish. In a negative conditioning‐learning assay nitrate treatment significantly impaired decision making time, and caused a 3‐fold increase in the period of time the fish experienced a mild shock. Nitrite treated caused a 2‐fold increase in the period of shock at the beginning of the assay, but the fish were able to learn with time. Taken together the behavioral assays demonstrate that both nitrate and nitrate treatments altered cognitive function in zebrafish and metabolomics on brains is being undertaken to understand the mechanisms contributing to these phenotypes.Support or Funding InformationOregon Agricultural Experiment Station, Endowment for the Celia Strickland and G. Kenneth Austin III Endowed Professor of Public Health

Microenvironmental characteristics and physiology of biofilms in chronic infections of CF patients are strongly affected by the host immune response.

In vitro studies of Pseudomonas aeruginosa and other pathogenic bacteria in biofilm aggregates have yielded detailed insight into their potential growth modes and metabolic flexibility under exposure to gradients of substrate and electron acceptor. However, the growth pattern of P.aeruginosa in chronic lung infections of cystic fibrosis (CF) patients is very different from what is observed invitro, for example, in biofilms grown in flow chambers. Dense invitro biofilms of P.aeruginosa exhibit rapid O2 depletion within <50-100μm due to their own aerobic metabolism. In contrast, invivo investigations show that P.aeruginosa persists in the chronically infected CF lung as relatively small cell aggregates that are surrounded by numerous PMNs, where the activity of PMNs is the major cause of O2 depletion rendering the P.aeruginosa aggregates anoxic. High levels of nitrate and nitrite enable P.aeruginosa to persist fueled by denitrification in the PMN-surrounded biofilm aggregates. This configuration creates a potentially long-term stable ecological niche for P.aeruginosa in the CF lung, which is largely governed by slow growth and anaerobic metabolism and enables persistence and resilience of this pathogen even under the recurring aggressive antimicrobial treatments of CF patients. As similar slow growth of other CF pathogens has recently been observed in endobronchial secretions, there is now a clear need for better invitro models that simulate such invivo growth patterns and anoxic microenvironments in order to help unravel the efficiency of existing or new antimicrobials targeting anaerobic metabolism in P.aeruginosa and other CF pathogens. We also advocate that host immune responses such as PMN-driven O2 depletion play a central role in the formation of anoxic microniches governing bacterial persistence in other chronic infections such as chronic wounds.

Effects of nitrate supplementation in trained and untrained muscle are modest with initial high plasma nitrite levels.

Nitrate (NO3-) supplementation resulting in higher plasma nitrite (NO2-) is reported to lower resting mean arterial blood pressure (MAP) and oxygen uptake (VO2 ) during submaximal exercise in non-athletic populations, whereas effects in general are absent in endurance-trained individuals. To test whether physiologic effects of NO3- supplementation depend on local muscular training status or cardiovascular fitness, male endurance-trained cyclists (CYC, n=9, VO2 -max: 64±3mL/min/kg; mean±SD) and recreational active subjects serving as a control group (CON, n=8, 46±3mL/min/kg), acutely consumed nitrate-rich beetroot juice ([NO3-] ~9mmol) (NIT) or placebo (PLA) with assessment of resting MAP and energy expenditure during moderate intensity (~50% VO2 -max) and incremental leg cycling (LEG-ex) and arm-cranking exercise (ARM-ex). NIT increased (P<.001) resting plasma NO3- by ~1200% relative to PLA. Plasma NO2- increased ~25% (P<.01) with a significant change only in CYC. LEG-ex VO2 (~2.60L/min), ARM-ex VO2 (~1.14L/min), and resting MAP (~87mm Hg) remained unchanged for CYC, and similarly for CON, no changes were observed for LEG-ex VO2 (~2.03L/min), ARM-ex VO2 (~1.06L/min), or resting MAP (~85mm Hg). VO2 -max was not affected by supplementation, but incremental test peak power was higher (P<.05) in LEG-ex for CYC in NIT relative to PLA (418±47 vs 407±46W). In both CYC and CON, high initial baseline values and small increases in plasma NO2- after NIT may have lowered the effect of the intervention implying that muscular and cardiovascular training status is likely not the only factors that influence the physiologic effects of NO3- supplementation.

The Acceptor Side of Photosystem II Is the Initial Target of Nitrite Stress in Synechocystis sp. Strain PCC 6803.

Nitrite, a common form of inorganic nitrogen (N), can be used as a nitrogen source through N assimilation. However, high levels of nitrite depress photosynthesis in various organisms. In this study, we investigated which components of the photosynthetic electron transfer chain are targeted by nitrite stress in Synechocystis sp. strain PCC 6803 cells. Measurements of whole-chain and photosystem II (PSII)-mediated electron transport activities revealed that high levels of nitrite primarily impair electron flow in PSII. Changes in PSII activity in response to nitrite stress occurred in two distinct phases. During the first phase, which occurred in the first 3 h of nitrite treatment, electron transfer from the primary quinone acceptor (QA) to the secondary quinone acceptor (QB) was retarded, as indicated by chlorophyll (Chl) a fluorescence induction, S-state distribution, and QA- reoxidation tests. In the second phase, which occurred after 6 h of nitrite exposure, the reaction center was inactivated and the donor side of photosystem II was inhibited, as revealed by changes in Chl fluorescence parameters and thermoluminescence and by immunoblot analysis. Our data suggest that nitrite stress is highly damaging to PSII and disrupts PSII activity by a stepwise mechanism in which the acceptor side is the initial target. IMPORTANCE In our previous studies, an alga-based technology was proposed to fix the large amounts of nitrite that are released from NOX-rich flue gases and proved to be a promising industrial strategy for flue gas NOX bioremediation (W. Chen et al., Environ Sci Technol 50:1620-1627, 2016, https://doi.org/10.1021/acs.est.5b04696; X. Zhang et al., Environ Sci Technol 48:10497-10504, 2014, https://doi.org/10.1021/es5013824). However, the toxic effects of high concentrations of nitrite on algal cells remain obscure. The analysis of growth rates, photochemistry, and protein profiles in our study provides important evidence that the inhibition by nitrite occurs in two phases: in the first phase, electron transfer between QA- and QB is retarded, whereas in the second, the donor side of PSII is affected. This is an excellent example of investigating the "early" inhibitory effects (i.e., within the first 6 h) on the PSII electron transfer chain in vivo This paper provides novel insights into the mechanisms of nitrite inhibition of photosynthesis in an oxygenic phototrophic cyanobacterium.

Water quality as an indicator of the health status of agro-pastoral dams' ecosystems in Benin: An ecosystem services study

Based on a study in three agro-pastoral dams in Nikki, Sakabansi and Fombawi in northern Benin, this article aims to characterize their physical, chemical and microbiological water quality. The ecosystem services framework underlies this article. Water of the three dams was sampled in the field and analysed at the laboratory. Means of variables were compared with standard values (norms) for drinking water set by both Benin and the World Health Organization. Agro-pastoral dams' water quality is problematic because of the significantly high levels of nitrite, nitrate, iron, and chemical oxygen demand. Water in these dams is unsuitable for both human and livestock consumption because it is contaminated with harmful bacteria including total Coliform, Escherichia coli, spores of Clostridium, Enterococcus feacalis, Salmonella typhi, Salmonella typhimurium, Salmonella enteritidis and Campylobacter jejuni. This study concluded that one solution for maintaining agro-pastoral ecosystem health consisted of watershed management based on monitoring ecosystem services such as water quality.

Proteomic analysis of 4-hydroxynonenal and nitrotyrosine modified proteins in RTT fibroblasts

Rett syndrome (RTT) is a pervasive developmental disorder, primarily affecting girls with a prevalence of 1 in every 10,000 births. A clear etiological factor present in more than 90% of classical RTT cases is the mutation of the gene encoding methyl-CpG-binding protein 2 (MECP2). Recent work from our group was able to shown a systemic oxidative stress (OxS) in these patients that correlates with the gravity of the clinical features.Using freshly isolated skin fibroblasts from RTT patients and healthy subjects, we have performed a two-dimensional gel electrophoresis in order to evidence the oxidative modifications of proteins with special focus on the formation of protein adducts with 4-hydroxynonenal (4-HNE PAs)—a major secondary product of lipid peroxidation— and Nitrotyrosine, a marker derived from the biochemical interaction of nitric oxide (NO) or nitric oxide-derived secondary products with reactive oxygen species (ROS). Then, oxidatively modified spots were identified by mass spectrometry, LC-ESI-CID-MS/MS.Our results showed that 15 protein spots presented 4-HNE PAs and/or nitrotyrosine adducts in fibroblasts proteome from RTT patients compared to healthy control cells. Post-translationally modified proteins were related to several functional categories, in particular to cytoskeleton structure and protein folding. In addition, clear upregulated expression of the inducible NO synthase (iNOS) with high nitrite levels were observed in RTT fibroblasts, justifying the increased nitrotyrosine protein modifications.The present work describes not only the proteomic profile in RTT fibroblasts, but also identifies the modified proteins by 4-HNE and nitrotyrosine. Of note, for the first time, it appears that a dysregulation of NO pathway can be associated to RTT pathophysiology. In conclusion, the evidence of a wide range of proteins able to forms adducts with 4-HNE, Nitrotyrosine or with both confirms the possible alteration of several aspects of cellular functions that well correlates to the complex clinical features of RTT patients.

Treatment of murine visceral leishmaniasis using an 8-hydroxyquinoline-containing polymeric micelle system

New therapeutics are urgently needed to treat visceral leishmaniasis (VL). Due to the fact that drug discovery is a long and expensive process, the development of delivery systems to carry old and toxic drugs could be considered, as well as the evaluation of new molecules that have already shown to present biological activity. In this context, the present study evaluated the in vitro and in vivo antileishmanial activity of an 8-hydroxyquinoline (8-HQN)-containing polymeric micelle (8-HQN/M) system against Leishmania infantum, the main causative agent of VL in the Americas. The experimental strategy used was based on the evaluation of the parasite load by a limiting-dilution technique in the spleen, liver, bone marrow and draining lymph nodes of the infected and treated animals, as well as by a quantitative PCR (qPCR) technique to also assess the splenic parasite load. The immune response developed was evaluated by the production of IFN-γ, IL-4, IL-10, IL-12 and GM-CSF cytokines, as well as by antileishmanial nitrite dosage and antibodies production. Hepatic and renal enzymes were also investigated to verify cellular injury as a result of treatments toxicity. In the results, 8-HQN/M-treated mice, when compared to the other groups: saline, free amphotericin B (AmpB, as a drug control), 8-HQN and B-8-HQN/M (as a micelle control) showed more significant reductions in their parasite burden in all evaluated organs. These animals also showed an antileishmanial Th1 immunity, which was represented by high levels of IFN-γ, IL-12, GM-CSF and nitrite, associated with a low production of IL-4 and IL-10 and anti-Leishmania IgG1 isotype antibodies. In addition, any hepatic or renal damage was found in these treated animals. In conclusion, 8-HQN/M was effective in treating L. infantum-infected BALB/c mice, and can be considered alone, or combined with other drugs, as an alternative treatment for VL.

RNA-seq analyses reveal insights into the function of respiratory nitrate reductase of the diazotroph Herbaspirillum seropedicae.

Herbaspirillum seropedicae is a nitrogen-fixing β-proteobacterium that associates with roots of gramineous plants. In silico analyses revealed that H. seropedicae genome has genes encoding a putative respiratory (NAR) and an assimilatory nitrate reductase (NAS). To date, little is known about nitrate metabolism in H. seropedicae, and, as this bacterium cannot respire nitrate, the function of NAR remains unknown. This study aimed to investigate the function of NAR in H. seropedicae and how it metabolizes nitrate in a low aerated-condition. RNA-seq transcriptional profiling in the presence of nitrate allowed us to pinpoint genes important for nitrate metabolism in H. seropedicae, including nitrate transporters and regulatory proteins. Additionally, both RNA-seq data and physiological characterization of a mutant in the catalytic subunit of NAR (narG mutant) showed that NAR is not required for nitrate assimilation but is required for: (i) production of high levels of nitrite, (ii) production of NO and (iii) dissipation of redox power, which in turn lead to an increase in carbon consumption. In addition, wheat plants showed an increase in shoot dry weight only when inoculated with H. seropedicae wild type, but not with the narG mutant, suggesting that NAR is important to H. seropedicae-wheat interaction.

Effects of Gas Flaring on the Physicochemical and Microbiological Quality of Water Sources in Egbema, Imo State, Nigeria

This study evaluates the effects of gas flaring on the physico-chemical and microbiological characteristics of water sources at Egbema, Imo State, Nigeria. Surface and ground water samples from the area were compared with samples from Ihiagwa Autonomous Community in Owerri West, a non-gas flared community. Both water sources were then compared with WHO standards for drinking water. The results revealed that water sources from the gas flared area have high levels of temperature, total chlorine, nitrate, nitrites, sulphates, calcium, and zinc, chromium with a very acidic pH when compared with water from non-gas flared sources. Also, microbial load increased the farther the distance from the flare site. The human health imparts of the presence of heavy metals and microorganisms in drinking water had been reported. In conclusion, gas flaring can pollute water sources within oil and gas facilities, thereby making them unsuitable for human consumption. Oil and gas industries should therefore treat water within their areas of operations before discharged into water bodies in addition to other remediation measures as part of their social responsibility.

Dietary Nitrate and the Epidemiology of Cardiovascular Disease: Report From a National Heart, Lung, and Blood Institute Workshop.

In view of continuing unanswered questions regarding the geographical and demographic distribution of cardiovascular disease, and recent discoveries about the effects of dietary nitrate on cardiovascular physiology, the National Heart, Lung, and Blood Institute (NHLBI) convened a workshop to

Effects of Gas Flaring on the Physicochemical and Microbiological Quality of Water Sources in Egbema, Imo State, Nigeria

This study evaluates the effects of gas flaring on the physico-chemical and microbiological characteristics of water sources at Egbema, Imo State, Nigeria. Surface and ground water samples from the area were compared with samples from Ihiagwa Autonomous Community in Owerri West, a non-gas flared community. Both water sources were then compared with WHO standards for drinking water. The results revealed that water sources from the gas flared area have high levels of temperature, total chlorine, nitrate, nitrites, sulphates, calcium, and zinc, chromium with a very acidic pH when compared with water from non-gas flared sources. Also, microbial load increased the farther the distance from the flare site. The human health imparts of the presence of heavy metals and microorganisms in drinking water had been reported. In conclusion, gas flaring can pollute water sources within oil and gas facilities, thereby making them unsuitable for human consumption. Oil and gas industries should therefore treat water within their areas of operations before discharged into water bodies in addition to other remediation measures as part of their social responsibility.